Rotary zigzag folding apparatus



July 20, 1965 E. D. NYsTRAND,

ROTARY ZIGZAG FOLDING APPARATUS 3 Sheets-Sheet 1 Filed Aug. 27, 1963 July 20, 1955 E. D. NYsTRAND 3,195,882

` ROTARY ZIGZAG' FOLDING APPARATUS v Filed Aug. 27, 1963 5 Sheets-Sheet 2l July 20 1965 E. D. NYSTRAND ROTARY ZIGZAG FOLDING APPARATUS 3 Sheets-Sheet 3 4Filed Aug.; 27, 1965 hlllllll! [mm] III I 'Il IllllL mg/1 555cm? yUnited States Patent O 3,195,882 ROTARY ZlGZAG FOLDING APPARATUS IErnst Daniel Nystrand, Green Bay, Wis., assigner to Paper Converting Machine Co., Inc., Green Bay, Wis. Filed Aug. 27, 1963, Ser. No. 305,244 13 Claims. (Cl. 27h-73) Th-is invention relates to folding apparatus, and, more particularly, apparatus for folding continuous webs in a reverse fashion.

This application is a continuation-in-part of my copending application, Serial No. 287,649, filed June 13, 1963, now abandoned.

The invention finds utility, for example, in the production of office forms which are provided in reversely lfolded lengths, suitable for detachment. In this environment, the reverse folding devices have limited the speed of production. Although the other elements (printer, perforator, etc.) making up the machine for providing a continuous reversely-folded form may be operated at substantially higher speeds, the folding device portion has been limited to speeds generally below 25() feet per minute. The provision of a device which materially increases the speed of the overall folded sheet-producing machine thus constitutes an important objective of the invention.

Another object of the invention is to provide a novel folding device made up of gripping elements and tucking elements wherein the parts are arranged so as to provide optimum operation. Still another object is to provide a folding apparatus wherein each of the tuckers lies within the pitch diameter of its gear, while each of the grippers project-s beyond the gear pitch l-ine. Other objects and advantages of the invention may be seen in the details of construction and operation set down in this specification.

The invention is described in conjunction with the accompanying drawing, in which:

FIG. 1 is a fragmentary elevational View, partially in section, of folding apparatus featuring a pair of identical rolls each equipped with grippers and tuckers for performing the folding operation;

FIGS. 2 and 3 are enlarged fragmentary elevational views of the camming mechanism of FIG. 1 and showing the positions of the gripper blades relative to the gripper anvils;

FIG. 4 is an even more enlarged View of a fragment of a cooperating gripper and tucker, with these two elements in various stages of cooperation in developing a fold; FIG. 5 is a fragmentary perspective view of paper folded by the mechanism of the other views;

FIG. 6 is a fragmentary top plan view of the camming mechanism of FIGS. 2 and 3;

FIG. 7 is a fragmentary end elevational View of the folding apparatus as would be seen along the sight line 7-7 of FIG. 8;

FIG. 8 is a fragmentary side elevational view of the FIG. 7 showing; and

FIG. 9 is a diagrammatic end View of the upper and lower folding rolls, better showing that the release points of the web are well below the centers of said rolls.

Although the basic reverse folding operation is well known, it is believed that a brief summary of the operation in general will be helpful to an understanding of the invention.

Operation in general To form the continuous reversely-folded ofiice form 10 of FIG. 5, a continuous web 11 (FIG. 1) is passed between rolls 12 and 13, thereby developing the alternate folds 10a, 10b, 10c, etc., of FIG. 5.

The structure responsible for this operation is usually ICC provided as part of other mechanism, some of which will be described in greater detail hereinafter. In any event, the web 11 is passed between r0ll-like members 12 and 13 (see FIG. l). It will be noted that the so-called rolls of FIG. 1 are not cylinders in the usual connotation of the word, being in effect four-sided in cross section. However, since they rotate and are used in this environment, the common parlance is employed. It will be appreciated that other configurations may be employed, the important matter being that each roll is equipped with tucker-s and grippers. This general arrangement is well known, as shown in Christman Patent 1,761,517, to which reference may be made for details not shown herein.

One tucker is designated 14 and the other is seen in the operating position of folding and is generally designated by the numeral 15. These are spaced apart -in the `so-called square roll 12, with a pair of grippers 16 and 17 positioned also 180 apart and spaced equally from the tuckers 14 and 15.

Roll 13 is also equipped with a pair of grippers, one of which is designated 18 and the other of which is in the operating position generally designated 19. In FIG. 1, it is seen, therefore, that the tucker 15 is arranged in juxtaposition to the gripper 19 to effect a folding operation.

In a fashion analogous to the showing of the roll 12, the roll 13 is equipped with a pair of tuckers designated 20 and 21. Thus, to provide a series of reverse folds, the tucker of one roll engages the gripper of the other roll, after which the gripper of the first roll is engaged by the tucker of the second roll. From this, it will be seen that, as a minimum, each roll must have at least one gripper and one tucker. Depending upon the geometry permissible, a larger number of fol-ding elements may be employed, as in FIG. 1, each roll being equipped with a pair of truckers and a pair of grippers.

Referring now to FIG. 2, it will be seen that the gripper 19 illustrated there is made up of an anvil 22 and a linger or blade 23. In FIG. 3, the jaw defined by the gripper anvil 22 and Ithe blade 23 is seen to be in closed condition, which is the condition reached at the conclusion of a given folding step.

To power the apparatus, gears such as shown at 24 and 2S in FIGS. 7 and 8 are employed, although it will be appreciated that other driving means may be employed for the rolls 12 and 13. In FIG. 4, these gears are represented by the dashed lines PLM and PL25, which represent respectively the pitch diameters or lines for the two gears 24 and 25 and also which aid in understanding the sequence of folding. It will be noted that the tucker 15 is shorter than the radius defining the pitch line PLM, while the gripper 19 projects beyond the pitch line PL25. In this significant respect, the inventive construction differs Vfrom what has gone before.

In FIG. 4, the tucker 15 is seen to be moving to the right and passing through various positions designated T1, T2, T3, etc., the corresponding positions of the anvil and blade of the gripper 19 being represented respectively by A1, B1; A2, Bz; etc- In FIG. 4, it is clearly seen that in the course of the folding operation the anvil 22 is catching up with the trailing face of the tucker 15, this while the blade 23 is in wiping engagement with the leading face of the tucker 15 (see particularly the stages designated T3 and T4). With this arrangement, a machine capable previously of only a maximum speed of 250 feet per minute is capable of being operated at speeds in excess of 500 feet per minute. The prior art constructions, as indicated above, had the tucker 15 projecting beyond its corresponding pitch line, while the gripper 19 did not extend as far as the pitch line on the gear associated with its roll. This meant that the peripheral speed of the tucker was greater than that of the gripper, so that the tucker was in effect moving away from the gripper anvil 22andholding the blade 23 away from the anvil. When the tucker 15 moved out from between the anvil and blade in theprior art construction, the'blade 23 snapped closed. on the anvil, developing a noticeable bounce, which materially limited the speed-of operation. With the inventive construction,

the tucker is seen to be leaving the gap dened by the gripper anvil 22V and gripper blade 23 just at the time .the gap is being closed..V Y

Environmental Vstructure T o further understand the mode of operation, reference is made. to FIG. 1- wherein theV numeral 26 designates the ,shaft of roll 12 and thel numeral 27 represents the shaft of roll 13.` These are designated alsotin FIGS. 7 and 8, and in those figures the numeral 2S, designates the side frames which provide the. support for. the rolls.

For this purpose,uthe side frames 28 are provided with lower bearing blocks as kat 29 and 30 (see especially FIG. 7).. Each lower bearing block is equipped with ayspring pedestal, only thel spring pedestal 31 associated withthe The Yspring pedestal A31'is releasably secured tothe bearing bearingY block 29 being seen, andV this in FIG. 8.

block 29 by means'of bolts 32 (also seen only in FIG. 8). Each side frame 28 isV equipped with a slot as at 33, -in

4which a pedestal 31 is mounted. M'ovably mounted within the slot 33 and above the springpedestal 31 is Van upper bearing block, Vthe upper bearing block associated with Ithe` lower bearing block 29, being designated 34, while the upper bearing block associated with ther lower' bearing block isv designated 35. Between each set ofupperV and lower' bearing'blocks is interposed a springas at 33a in FIG. v8. VThe position of theupper bearing blocks 34 and 35, and hence the shaft 26, is determined by means ofl setscrews 36 which bear against the upper face of the upper bearing blocks 34 and 35. In this fashion, the upper roll 12 is positionably mounted for. interaction with Vroll 13. Y' Y To regulate the opening and closingof the grippers, Le., to first space the blade 23 away from the anvil 22 and' thereafter bringit into, contacting relation, each roll a camv'follower 47 riding .againstthe cam 43. y A .Y Y

For'the purpose of dynamic balance, each rocker shaft isfequipped with a cam arm 46 at each end thereof riding against identical cams 4374and43 arranged on opperiphery of the posite sides of the machine, as `can ,beV seen best in FIG. 7.

The cam followersv47 are urged intocontacting relation with the cam periphery by means ofa spring 48 (see particularly FIG. 2) which is `interconnected between the cam arm 45 and a post 49 projecting horizontally from each end of the roll 12 or 13, as the vcase may be.

In operati-on, the gripper 19 inr FIG. l, in proceeding clockwise aroundthe stationary cam 43,'irst is closed,

Jie., the blade 23 being moved toward the vanvil 22 by .virtue of'spring'48, when the camfollower is in the portion rnarkedvSi).V Further yrotation of the member 13 brings the cam follower,V into the position Vdesignated 51, where a the Vjaw definedkby theanvil19`and blade23 is openthis being the kcondition illustrated relative Vto the gripper ,'18 in FIG. 1.., YThe jawjdeiinedby'they gripper Y18 remains open until the associated cam follower-passes the high point 52 of the cam 43..

As can 'be best seen from a consideration of FIG. 4, the tip 53 of the anvil 22 defines a cylindrical envelope,

Vas also does the tip 54 ofjthe tucker15. The two en- .velopes are so related that they diameter of thev envelope defined bythe anvil or gripper tip is greaterv than the diameter of the envelopedefined by the tu'cker tip.

Y The tuclrer and gripper arrangement described not only eliminates the heretofore-tolerated but objectionable bouncingof theblade at the lend of a tuckingfcycle .characteristic of theY prior art constructions because the tucker hadaV greater linear speed than the gripper-but there is also 'an advantageous elimination of Vvibration or ysnappingof the blade 23 when the blade 23 engages the tuclter midway through the tucking cycle.' This occurs midway between theA positions' designated T2 and T3 seen in FIG. 4,V where the relative greater velocity .of the gripper .insuresa light contact between the blade 23 and the leading face 575 of the tucker 15-thi-s notwithstanding the drop-off of the cam' contour as at 50. This soft 12'and 13 is. equipped with a camming mechanism, the Y `camming mechanism for the upper roll 12 being generally designated 37, while that for the lower yroll 13 isv generally approach of the gripper blade 23 to theftucker 15 makes possible the use of a resilientgripper blade, and an advantageous construction employs a blade as at 23 in .FIG 4, wherein the steel blade is equipped with a facing asat 23" consisting of a Ms thickness of polyethylene.

The resilient nature of this facing insures aV frictional engagement ofthe `blade 23 with the tucked-in portion of the web which is advantageous in maintaining the web in tucked Ycondition notwithstanding the retraction of the tucker 15. By virtue ,of employing a resilient blade con- Y structed of polyethylene, rubber, etc., a broader area` of portion of the; mechanism previously referred to includes Y a guide 41 and a stacking frame 42. It will beV appreciated that a wide `variety of delivery and discharge means may be employed, depending upon the final form ofthe reversely-folded product. In some cases, it may be advantageous to.include perforating .or punchingequipment alongiwith printing'presses,'and the like'. Y Y

The camming mechanism associated with the VVgripper' 19 vcan be seen most clearlyin FIGS. -2, 3 and 6. Referring first to FIGS. 2 and 3, the, cam for rollV 13 'isdes ignated 43 and one operative peripheral portion thereofis the fragment shown in those two views. Cams 43 and' 43', respectively,`are provided for the r'olls l12 and 13,`

and each cam hasy a high'point to alternatively actuate ythe Y grippers 18 "and 19, or 16 Vand-17, asthe case may be.

The cam 43,.'as seen in` FIG. 6, is secured to the frame 28 by means of bolts'44, and serves to rock theanvil finger 2.3' by means off'a bladev or rocker shaft 45 (see'par? ticularly FIGS-2,13 and 6). The rocker'shaft ,45 isY jour- Vna'led in a'be'ai'ing block 45a (see FIG. 2) provided as part of the carrying roll 12 or 13, as the case may be, and

at each end'the shaft 45v is equipped with a rocker arm 46 to developthe cam action through the movement of Contact between Athe bladey and the weby isafforded than -when utilizing only the tip of a metal blade characteristic of the prior.art'constructions. The maintenance of contact between'jthe blade and theV web is important when it is considered that these folding machines for zigzag Yfolds, interfolds,l andthe like, have substantial width, several letter-sized webs being carried through the machine simultaneously in side-by-side relation. f

- As` specific' examples ofthe invention, roll-like members 12 and 13 were constructed having 6.625'VIV pitch diameter gears; In each case, the apparatus was employed for a `1tf tuck andthe anvilv faces as at 55 were arranged at 30 to a radial lline. rThe tuckers, as represented by the tuckerf 15in FIG. 4, were constructed withfa trailing face 56 arrangedA at a 15 angle, as at 6. i The leading facer 57 of the ,tucker15 wasarranged at an angle of 30 relative to the radial line through the tip as at 54 in the T3 showing in FIG. 4." With thisV arrangement, optimum results were obtained with the tucker`tip`54being retracted 1A" from theV pitch line 24 ofV its associated gear, while the gripper Y '19 was extended 1/2* f beyond the pitch line 25 of its asso- Y ciated gear. Y

Another machinewas constructed wherein the pitch diameters of the gears 24 and 25 were 91/2" and for the same geometry of anvil face 55 and rake of the tucker rear face 56, along with the same amount of tuck. Again optimum performance was obtained with a 1/2 extension of the gripper beyond the pitch line of its gear and a l/i retraction of the tucker from the pitch diameter of its gear. I have found that the extension of the gripper beyond the pitch line of its associated gear and the retraction of the tucker from its gear pitch lineare functions of the angular relationship of the anvil and tucker faces as at 55 and 56 and the amount of tuck-best represented by the maximum entry of the tucker within the jaw defined by the anvil and blade configuration at the middle of the tucking cycle (see the configuration defined by the symbols T3, A3 and B3 in FIG. 4).

In the particular illustration given, with the face angles being 30 and 15 respectively for the faces 55 and 56 and with a 1A tuck, if the tucker 15 is not retracted, I rind that the anvil catches up to the tucker prior to the center position, i.e., T3. With a 1A retraction of the tucker 15, the anvil contacts the trailing face 56 of the tucker after the center point has been passed but before pull-out is reached, as at T5. On the other hand, if the retraction of the tucker is more than 1A, it is necessary to enlarge the apparatus so as to get a suitably iiat arc of travel of the tucker 15 to no apparent advantage.

In designing folding apparatus according to the invention, it will be seen that the variables just mentioned, the angular relationship of the faces 55 and 56 and the amount of tuck, define the gap G identified in FIG. 4. With a lesser amount of tuck, the gap G can be smaller, since the tucker enters the jaw deiined by the gripper elements at a point near the midpoint of the tucking cycle. Once the gap G is determined, the relative velocities of the tucker and gripper are established, since the gap G must disappear at the time of pull-out of the tucker 15, i.e., just prior to the position designated T5 in FIG. 4.

It will be appreciated that the invention has a wide variety of application, as previously indicated. The web or webs being folded can take the form of zigzag folds or interfolds, and the axes of the rolls 12 and 13 may be disposed horizontally, vertically, or `at intermediate angular positions. In the specic illustration given, the axes 'of the shafts 26 and 27 (see FIG. 8) are disposed horizontally.

In FIG. 9, it is seen that the release points of the web are well below the center lines of the upper `and lower folding rolls. I find that this delivery arrangement permits material increase in speed of operation. Also, the gripper release in the lower roll 13 may be operated slightly in advance of opening the gripper in the upper roll l2 because of the sharper bend in the web as at 58.

In the illustration given, particularly with respect to FIG. 9, it is seen that the release point on the member l2 is about 45 past the low point, while that on the member 13 is about 135 past the high point, i.e., the point of common tangency. The substantially simultaneous release under these conditions develops a compact stack since the weight of the 96 included length of web causes the continuous web to fall into the desired position. This operation is achieved by suitably contouring the cams 43.

While in the foregoing specification a detailed description of the invention has been set down for the purpose of explanation thereof, many variations in the details herein given may be made by those skilled in the art without departing from the spirit and scope of the invention.

I claim:

I. In folding apparatus, a frame, a pair of members journaled in said frame in parallel, side-by-side relation, means for rotating said members at the same angular velocity, means for feeding a web between said members,

'each of said members being equipped with at least one tucker element and one gripper element, said members being so oriented relative to each other to position the tucker element of one member in web-tucking engagement with the gripper element of the other member to cooperate in folding said web, the movement of the tip of each member defining a cylindrical envelope, with the envelope of each gripper element tip having a greater diameter than the envelope of each tucker element, said rotating means being constructed to rotate the gripper element tip at a greater lineal velocity than the tucker element tip during folding.

2. Apparatus for zigzag folding of a continuous web, comprising a frame, a pair of substantially identical folding members journaled in said frame for rotation about parallel axes, a substantially identical gear affixed to each member with said gears in intermeshed relation along the pitched diameters thereof, means for rotating one of said gears whereby said members are rotated at the same angular velocity, means for feeding a web between said members, each member having at least two tuckers and two grippers arranged to zigzag fold said web, each of said tuckers including a tip rigidly fixed to its associated member and with said tucker tip being positioned inside the pitch diameter of its assocated gear, each of said grippers including an anvil tip fixed to its associated member with said anvil tip projecting beyond the pitch diameter of its associated gear, whereby each anvil tip has a greater lineal velocity than each tucker tip during folding, each gripper further including a blade resiliently connected to its associated member and arranged to lead the tucker of the other member which coacts therewith in developing a fold while the coacting anvil tip trails the coacting tucker.

3. In folding apparatus, a frame, a pair of members journaled in said frame in parallel, side-by-side relation, means for rotating said members at the same angular velocity, means for feeding a web between said members, each of said members being equipped with at least one rigidly mounted tucker element and one gripper element, said members being so oriented relative to each other to position the tucker element of one member in web-tucking engagement with the gripper element of the other member to cooperate in folding said web, each gripper element including a rigidly mounted anvil and a movable blade defining a web-folding jaw, means on said frame for pivoting said blade away from said anvil to permit said tucker to enter said jaw, the tip of said anvil being on a greater radius than the tip of said tucker element whereby said anvil tip has a greater lineal speed 4than said tucker element tip during folding and said elements being arranged that when said jaw is open and said tucker element is positioned between said blade and anvil, further rotation of said members results in reduction of the opening of said jaw, with said anvil approaching said tucker element and said blade approaching said anvil.

4. The structure of claim 3 vin which said blade is equipped with a resilient face disposed in confronting relation with said anvil.

5. In folding apparatus, a frame, a pair of members journaled in said frame in parallel, side-by-side relation, means for rotating said members at the same angular velocity, means for feeding a web between said members, each of said members being equipped with at least two rigidly mounted tucker elements and two gripper elements, said members being so oriented relative to each other to position the tucker element of one member in web-tucking engagement with the gripper element of the other member to cooperate in folding said web, each gripper element including a rigidly mounted anvil and a movable blade defining a web-folding jaw, means on said frame for pivoting said jaw away from said anvil to permit said tucker to enter said jaw, the tip of said anvil being on a greater radius than the tip of said tucker element whereby said anvil tip has a greater lineal speed than said tucker element tip during folding and said elements being arranged that when said jaw is open and said tucker element is positioned between said blade and anvil, further rotation of said members results -in a reduction of the opening of said jaw, with saidanvil approaching said y Vtncker element and said blade approaching said anvil, vsaid tucker elementrbeing defined by Vangularlyjrelated,

Arigidly mounted Ytucker elements andtwo gripper-.elements, said members being sooriented relative to each other to position the tuckerv element ofone member in web-tucking engagement withgthe gripper element of the other member to cooperate' inV folding said web, each gripper element including-a rigidly mounted anvil and a lmovable blade defining a web-folding jaw, means on saidV frame for pivoting said blade away from said anvilV toY permit said tucker to enter said jaw, the-tip of saidv anvil being on a greater radius than the Vtip of said tucker elel tucker element face l annessa f8 the axis of its associated member than the radiusv t0 the anvil end from the axis of itsassociated member, whereby each anvil endhasa greater 'lineal speed during folding than the end of each tucker. n t

9. Web folding apparatus, comprising a frame, a pair v of folding membersl journaled in said frame for rotation `about parallel axes, means for rotating said members, vmeans fior. feeding a web between said members, each memberv having at least one tucker and one gripper, each tucker being rigidly fixed'to its asso'ciatedmember,

. each gripper including lan anvil rigidly fixed to its associ- -ated'member and a blade pivotally mounted on its associated member, Vsaid blade leading said tucker during foldingiand said yanvil trailing saidl blade during folding, said tucker having a smaller radius to the endthereof from the axes of Yits associated member than the radius to the anvil end, from the axis of its associated member, said rotating means being constructed to rotate each anvil end at a vgreater lineal speedduring folding thanv the end of each tucker, saidV tucker being defined byangularly-related n faces converging toY define the tucker.k end with one tucker face .being in confronting relation during 'folding with a faceon said anvil, theothertucker face being in confrontment whereby'said anvil tip has a greater lineal speedV than said tuckerf'element tip u during folding and said elements being arranged that when said jaw is open and y said tucker element is positioned between said blade and anvil, further rotation of said members results in reduction of the opening of said jaw, with said anvil approachv ing said tucker element and said blade approachingsaid anvil, said frame being equipped with Vmeans for opening each gripper element to releasethe web confined therein, said opening means being operative to release'said web when the associated gripper element'is below therotational axis ofk its associated member, said members being positioned with their axes, verticallyV spaced apart. p

7. Apparatus for zigzag folding ofa continuous web,

comprising'a frame, a pair of 4identicalYfolding'members journaled in said frame for rotation about parallel axes,

an identical gear aixed to each member with said'` gears in intermeshed relation along the pitch diameters thereof, means for rotating one of said gears whereby said members are rotated at the same angular velocity, meansfor feeding a web between said members, each member having at least Vtwo :tuckers and two grippersfarranged toy zigzag fold said web, each Vof said tuckers including` a Vtip rigidly fixed to itsA associated member and with saidV tucker tip being positioned inside-the pitch diameterfof its associated gear, each of said grippers yincluding an anvil' .jecting beyond the pitch diameter ofrits associated'gear,

jectingbeyond the pitch'diameter of its assocated gear,

whereby the anvil Vtip has a greatervlinear speed during folding than the tucker tip, each gripper further including a blade resiliently connected to itsy associated member'and arranged t0 lead the tucker of the kother member which coacts therewith in developing a fold while the 'coacting anvil tip trails the coacting tucker, saidy membersy being positioned` with their rotational axes-"vertically spaced apart, sad frame being equipped with ajcam foreach member for controlling the movement of thel blade associated therewith, said cams being contoured to release a web fold from each gripper ati a'point about 45 below the roll axis associated therewith.

8. Web folding apparatus, comprising a frame, a, pair of folding members journaled in said frame for Vrotation about parallel axes, means -for rotating saidvmembers at the same angular speed, means for feeding aweb between said members, each member having at least oneV tucker'and one gripper arranged to fold said web,` each ing relation'with said blade during folding, the angle between the face of said tucker confronting said.` anvil face and a radial line drawn to the tucker end being smaller .than the' angle defined by said radial line and the face of said tuckerrconfronting said blade, said anvil face being disposed'at an acute angle to radial drawn from the axis of its associated member with the -angle, between theanvil face andtheradialline associated therewith being greater than the'fangle between the tucker face confronting said anvil face and the radial line associated therewith.

' 14D. In folding'apparatus, a frame,- a pair of members journaled in said frame in'parallel, side-by-side relation,

means for 'rotating said members, means forrfeeding a web between said` members, each `,of said members being equipped with at least on-e ltucker element and one gripper element, said members being so oriented with respect to each other as to position the tucker element of one member in web tucking engagement with the gripper element 'of the other memberto cooperate` in folding said web, vthe. movement of each Vmember defining a cylindrical e envelope, with the envelope ofeach'gripper element having a gri-eater diameter than the envelope of each tucker element, said 'rotating means including a gear vfor each member defining a pitch diameter, each of said tucker elements Vbeing spaced .radially inwardly ofthe pitch Vv.diameter of its associated gear, ther-tip of each gripper element being positioned radially outwardly -of the pitch diameter of its associated gear, each grippery element including an anvilanda blade cooperable to receive a web tuckedtherebetween ,byits cooperating tucker element, said anvil'y and cooperating tucker element having confronting faces angularly related'to eachother, thedistance between the anvil of each tucker member and the pitch diameter'of its associated gear being a function of '(1) the extent :to which the web isV tucked between the anvil and blade, and (2) the angular relation ofsaid faces. Y

11. The structure of claim, 1li inY which each face defines an acute angle with a radial line' drawn from the envelope center tothe element tip, the angle associated with the anvil face lbeing greater than the angle associated with the tucke'r face.. Y 1

12.' Thestructure of claimY 11 in which the gripper element angle is about :30 and the tucker element angle 13. Web folding apparatus,rcomprising Ya frame, a pair of folding members journaled in'said frame for rotation about parallel axes, means for rotating said members at y the same angular speed, means for-feeding a web between member, said blade' leading said tucker during folding and said anvil trailing said fblade during folding, said tucke'r having a smaller radius to the end thereof from 9 l0 gipper including an anvil rigidly Xed to its associated References Cited bythe Examiner member and a blade pivotally mounted on its associated UNITED STATES PATENTS member, said blade leading said tucker during folding and from the axis of its associated member whereby each anvil end has a greater lineal speed during folding than ENGENE Rl CAPOZIO, Primary @Mmmmthe end of each tucker. 

1. IN FOLDING APPARATUS, A FRAME, A PAIR OF MEMBER JOURNALED IN SAID FRAME IN PARALLEL, SIDE-BY-SIDE RELATION, MEANS FOR ROTATING SAID MEMBERS AT THE SAME ANGULAR VELOCITY, MEANS FOR FEEDING A WEB BETWEEN SAID MEMBERS, EACH OF SAID MEMBERS BEING EQUIPPED WITH AT LEAST ONE TUCKER ELEMENT AND ONE GRIPPER ELEMENT, SAID MEMBERS BEING SO ORIENTED RELATIVE TO EACH OTHER TO POSITION THE TUCKER ELEMENT OF ONE MEMBER IN WEB-TUCKING ENGAGEMENT WITH THE GRIPPER ELEMENT OF THE OTHER MEMBER TO COOPERATE IN FOLDING SAID WEB, THE MOVEMENT OF THE TIP OF EACH MEMBER DEFINING A CYLINDRICAL ENVELOPE, WITH THE ENVELOPE OF EACH GRIPPER ELEMENT TIP HAVING A GREATER DIAMETER THAN THE ENVELOPE OF EACH TUCKER ELEMENT, SAID ROTATING MEANS BEING CONSTRUCTED TO ROTATE THE GRIPPER ELEMENT TIP AT A GREATER LINEAL VELOCITY THAN THE TUCKER ELEMENT TIP DURING FOLDING. 